In line with the lower cost per bit of flash memory, flash memory has come to be used as a storage medium in storage systems in recent years. For configurational reasons, this flash memory can only guarantee data storage up to a limited number of erases. Therefore, in a storage system that utilizes flash memory, for example, steps are taken so as to extend the life of the storage system as long as possible by limiting the number of erases, limiting the write data size, and deleting data on a regular basis.
For example, technology, whereby a storage controller for controlling multiple flash memory packages carries out wear leveling (leveling) among flash memory packages in a storage system, which comprises multiple flash memory packages comprising flash memory chips, based on the frequency of updates with respect to the actual write throughput of data when a new flash memory package is added, is known (for example, refer to Patent Literature 1).